package com.yu.test.image;

import java.awt.*;
import java.util.Random;

/**
 * Created by xiaolongyu on 15/6/2.
 */
public class PixelUtils {
    public final static int REPLACE = 0;
    public final static int NORMAL = 1;
    public final static int MIN = 2;
    public final static int MAX = 3;
    public final static int ADD = 4;
    public final static int SUBTRACT = 5;
    public final static int DIFFERENCE = 6;
    public final static int MULTIPLY = 7;
    public final static int HUE = 8;
    public final static int SATURATION = 9;
    public final static int VALUE = 10;
    public final static int COLOR = 11;
    public final static int SCREEN = 12;
    public final static int AVERAGE = 13;
    public final static int OVERLAY = 14;
    public final static int CLEAR = 15;
    public final static int EXCHANGE = 16;
    public final static int DISSOLVE = 17;
    public final static int DST_IN = 18;
    public final static int ALPHA = 19;
    public final static int ALPHA_TO_GRAY = 20;

    private static Random randomGenerator = new Random();

    /**
     * Clamp a value to the range 0..255
     */
    public static int clamp(int c) {
        if (c < 0)
            return 0;
        if (c > 255)
            return 255;
        return c;
    }

    public static int interpolate(int v1, int v2, float f) {
        return clamp((int)(v1+f*(v2-v1)));
    }

    public static int brightness(int rgb) {
        int r = (rgb >> 16) & 0xff;
        int g = (rgb >> 8) & 0xff;
        int b = rgb & 0xff;
        return (r+g+b)/3;
    }

    public static boolean nearColors(int rgb1, int rgb2, int tolerance) {
        int r1 = (rgb1 >> 16) & 0xff;
        int g1 = (rgb1 >> 8) & 0xff;
        int b1 = rgb1 & 0xff;
        int r2 = (rgb2 >> 16) & 0xff;
        int g2 = (rgb2 >> 8) & 0xff;
        int b2 = rgb2 & 0xff;
        return Math.abs(r1-r2) <= tolerance && Math.abs(g1-g2) <= tolerance && Math.abs(b1-b2) <= tolerance;
    }

    private final static float hsb1[] = new float[3];//FIXME-not thread safe
    private final static float hsb2[] = new float[3];//FIXME-not thread safe

    // Return rgb1 painted onto rgb2
    public static int combinePixels(int rgb1, int rgb2, int op) {
        return combinePixels(rgb1, rgb2, op, 0xff);
    }

    public static int combinePixels(int rgb1, int rgb2, int op, int extraAlpha, int channelMask) {
        return (rgb2 & ~channelMask) | combinePixels(rgb1 & channelMask, rgb2, op, extraAlpha);
    }

    public static int combinePixels(int rgb1, int rgb2, int op, int extraAlpha) {
        if (op == REPLACE)
            return rgb1;
        int a1 = (rgb1 >> 24) & 0xff;
        int r1 = (rgb1 >> 16) & 0xff;
        int g1 = (rgb1 >> 8) & 0xff;
        int b1 = rgb1 & 0xff;
        int a2 = (rgb2 >> 24) & 0xff;
        int r2 = (rgb2 >> 16) & 0xff;
        int g2 = (rgb2 >> 8) & 0xff;
        int b2 = rgb2 & 0xff;

        switch (op) {
            case NORMAL:
                break;
            case MIN:
                r1 = Math.min(r1, r2);
                g1 = Math.min(g1, g2);
                b1 = Math.min(b1, b2);
                break;
            case MAX:
                r1 = Math.max(r1, r2);
                g1 = Math.max(g1, g2);
                b1 = Math.max(b1, b2);
                break;
            case ADD:
                r1 = clamp(r1+r2);
                g1 = clamp(g1+g2);
                b1 = clamp(b1+b2);
                break;
            case SUBTRACT:
                r1 = clamp(r2-r1);
                g1 = clamp(g2-g1);
                b1 = clamp(b2-b1);
                break;
            case DIFFERENCE:
                r1 = clamp(Math.abs(r1-r2));
                g1 = clamp(Math.abs(g1-g2));
                b1 = clamp(Math.abs(b1-b2));
                break;
            case MULTIPLY:
                r1 = clamp(r1*r2/255);
                g1 = clamp(g1*g2/255);
                b1 = clamp(b1*b2/255);
                break;
            case DISSOLVE:
                if ((randomGenerator.nextInt() & 0xff) <= a1) {
                    r1 = r2;
                    g1 = g2;
                    b1 = b2;
                }
                break;
            case AVERAGE:
                r1 = (r1+r2)/2;
                g1 = (g1+g2)/2;
                b1 = (b1+b2)/2;
                break;
            case HUE:
            case SATURATION:
            case VALUE:
            case COLOR:
                Color.RGBtoHSB(r1, g1, b1, hsb1);
                Color.RGBtoHSB(r2, g2, b2, hsb2);
                switch (op) {
                    case HUE:
                        hsb2[0] = hsb1[0];
                        break;
                    case SATURATION:
                        hsb2[1] = hsb1[1];
                        break;
                    case VALUE:
                        hsb2[2] = hsb1[2];
                        break;
                    case COLOR:
                        hsb2[0] = hsb1[0];
                        hsb2[1] = hsb1[1];
                        break;
                }
                rgb1 = Color.HSBtoRGB(hsb2[0], hsb2[1], hsb2[2]);
                r1 = (rgb1 >> 16) & 0xff;
                g1 = (rgb1 >> 8) & 0xff;
                b1 = rgb1 & 0xff;
                break;
            case SCREEN:
                r1 = 255 - ((255 - r1) * (255 - r2)) / 255;
                g1 = 255 - ((255 - g1) * (255 - g2)) / 255;
                b1 = 255 - ((255 - b1) * (255 - b2)) / 255;
                break;
            case OVERLAY:
                int m, s;
                s = 255 - ((255 - r1) * (255 - r2)) / 255;
                m = r1 * r2 / 255;
                r1 = (s * r1 + m * (255 - r1)) / 255;
                s = 255 - ((255 - g1) * (255 - g2)) / 255;
                m = g1 * g2 / 255;
                g1 = (s * g1 + m * (255 - g1)) / 255;
                s = 255 - ((255 - b1) * (255 - b2)) / 255;
                m = b1 * b2 / 255;
                b1 = (s * b1 + m * (255 - b1)) / 255;
                break;
            case CLEAR:
                r1 = g1 = b1 = 0xff;
                break;
            case DST_IN:
                r1 = clamp((r2*a1)/255);
                g1 = clamp((g2*a1)/255);
                b1 = clamp((b2*a1)/255);
                a1 = clamp((a2*a1)/255);
                return (a1 << 24) | (r1 << 16) | (g1 << 8) | b1;
            case ALPHA:
                a1 = a1*a2/255;
                return (a1 << 24) | (r2 << 16) | (g2 << 8) | b2;
            case ALPHA_TO_GRAY:
                int na = 255-a1;
                return (a1 << 24) | (na << 16) | (na << 8) | na;
        }
        if (extraAlpha != 0xff || a1 != 0xff) {
            a1 = a1*extraAlpha/255;
            int a3 = (255-a1)*a2/255;
            r1 = clamp((r1*a1+r2*a3)/255);
            g1 = clamp((g1*a1+g2*a3)/255);
            b1 = clamp((b1*a1+b2*a3)/255);
            a1 = clamp(a1+a3);
        }
        return (a1 << 24) | (r1 << 16) | (g1 << 8) | b1;
    }
}
